The Sound Transit Board of Directors Thursday updated the preferred alternative for the East Link light rail project. The preferred alternative was modified to include a shorter and lower-cost tunnel option in downtown Bellevue as well as a revised at-grade alternative through downtown. Inclusion of the tunnel was facilitated by the City of Bellevue agreeing to provide up to a $150 million contribution.

"We are moving two alignment options forward into preliminary engineering in downtown Bellevue -- one that includes a downtown Bellevue tunnel and one with an at-grade alignment," said Sound Transit Board Chair and Snohomish County Executive Aaron Reardon. "While carrying a higher cost, the tunnel option offers strong ridership and responds to the strong advocacy by the City of Bellevue and the city's term sheet for providing financial support."

Last fall, Sound Transit responded to Bellevue's interest in a tunnel by identifying an option that was shorter and an estimated $200 million less expensive than the tunnel option identified for further consideration in May 2009. Under a term sheet the Bellevue City Council adopted Monday night, the city would provide access to city property at no cost, provide one-time tax revenues generated by the project, provide in-kind services and assume responsibility for all or parts of East Link capital projects. The term sheet elements would generate up to $150 million to either reduce Sound Transit cost or increase Sound Transit funding.

While the identification of a preferred alternative is an important step in the process, it is not a final decision. All of the alternatives in the draft environmental impact statement will continue to be carried forward and evaluated. The Sound Transit Board will select the final East Link route in 2011 after completion of the final EIS. Sound Transit's Preferred Route

East Link construction is scheduled to start in late 2013 or early 2014. Service to Bellevue would open in 2020 under the at-grade option or 2021 under the tunnel option. Service to the Overlake area of Redmond is scheduled to open in 2021.

"Bellevue residents, businesses and city leaders believe that a tunnel represents the optimal light rail alignment through downtown Bellevue," said Sound Transit board and Bellevue council member Claudia Balducci. "By working creatively and constructively through many challenges, we identified a path forward for including the tunnel in the additional environmental and engineering work."

Extensive public involvement over the last year shaped Thursday's Sound Transit Board action, including public review and comment on the draft EIS, several open houses and design workshops and dozens of briefings for East King County residents and businesses. A strong majority of residents in East King County and across the region approved the East Link light rail extension as part of the 2008 Sound Transit 2 ballot measure.

The East Link preferred route Sound Transit adopted in 2009 included at-grade service through downtown Bellevue. Now, both an at-grade alignment and the tunnel will be advanced through preliminary engineering during the completion of the Final EIS, scheduled for publication in 2011.

South of downtown Bellevue, the updated preferred alternative serves the South Bellevue park-and-ride and continues north on 112th Avenue Southeast. Sound Transit and the City of Bellevue will work together to develop design options, and the Sound Transit Board will identify the specific configuration of light rail on 112th to move forward in the EIS and for preliminary engineering and mitigation analysis.

The Board expressed preference for the updated 112th Avenue Southeast route over the longer, more costly elevated trackway that curved east to I-405 and impacted an additional wetland and creek. The preferred alternative also reflects the Sound Transit Board's desire to provide service to the South Bellevue park-and-ride.

"Extending light rail across Lake Washington is a major priority for all of East King County," said Sound Transit Capital Projects Committee Chair and Issaquah City Council Deputy President Fred Butler. "While we work to extend light rail to other Eastside communities, the preferred alternative identified today offers great alternatives for transferring between light rail and buses."

East of downtown Bellevue, the board's preferred route continues to serve the Bel-Red corridor, Overlake Village and Microsoft's campus, running in a combination of elevated and at-grade alignments located parallel and just to the north of Bel-Red Road in Bellevue and adjacent to SR 520 in Redmond. The Board identified a retained cut 120th Station as preferred, but the design is subject to a term sheet with the developer providing assurances that Sound Transit’s costs would be equal to or lower than with an at-grade station. In Redmond, the Board modified the preferred alignment with a shorter potentially less expensive alternative that remains adjacent to SR 520 through the Overlake Village area, as proposed by the City of Redmond.

In all, the preferred East Link route runs approximately 18 miles east from downtown Seattle to Mercer Island and South Bellevue, crossing Lake Washington in center roadway of I-90. The first 14 miles to the Overlake Transit in Redmond are funded for construction and estimated to cost $2.4 billion (2007$) with a surface alternative in downtown Bellevue and $2.6 billion (2007$) with a tunnel. Under longstanding agreements with the state and local partners, the I-90 corridor is being readied for light rail by constructing new HOV lanes across the lake on the outer roadways, adding 24-hour HOV service both eastbound and westbound while preserving the existing number of general purpose lanes.

East Link will connect Mercer Island, Bellevue and Redmond to the Link light rail system that opened last year between downtown Seattle and Sea-Tac Airport and with the University Link line from downtown Seattle to the University of Washington opening in 2016. With the completion of Sound Transit 2 expansions in 2023, it will be part of a regional light rail system stretching 55 miles. When complete to downtown Redmond, the East Link line will serve up to 50,000 daily riders on one of the region’s most congested travel corridors.

While the Sound Transit 2 ballot measure does not fund a light rail segment between Overlake Transit Center and Redmond's downtown areas, the board identified a preferred route for a future connection that runs along State Route 520 and along the northern edge of Marymoor Park.